1. Field of the Invention
The present invention relates to orthopaedic implants, and more particularly, to articulating bearing surfaces for orthopaedic implants.
2. Description of the Related Art
Orthopaedic implants used to reconstruct a joint of a patient typically include two implant halves with each implant half defining an articulating bearing surface. For example, an orthopaedic knee implant includes a proximal component which is placed within the femur and a distal component which is placed within the tibia. The proximal component typically includes a metallic articulating bearing surface which pivots on a non-metallic articulating bearing surface defined by the tibial knee component. The non-metallic bearing surface may be formed from a block of ultra-high molecular weight polyethylene (UHMWPE), which is machined to define the articulating bearing surface. The non-metallic bearing surface is attached to and carried by a tibial tray, which in turn is affixed to a stem inserted within the intramedullary canal of the tibia.
The present invention provides a method of manufacturing an articulating bearing surface for use in an orthopaedic implant, wherein a crosslinked UHMWPE block is near-net shaped and reformed under heat and pressure to define a net shaped articulating bearing surface.
The invention comprises, in one form thereof, a method of manufacturing an articulating bearing surface for use in an orthopaedic implant. A block of ultra-high molecular weight polyethylene is irradiated with sufficient radiation energy to crosslink at least a portion of the ultra-high molecular weight polyethylene. The irradiated block is placed within a reforming apparatus having a complimentary articulating bearing surface. The block is heated and pressed against the complimentary articulating bearing surface, thereby forming the articulating bearing surface.
An advantage of the present invention is that a net shaped articulating bearing surface with improved surface finish, wear resistance, and abrasions resistance is provided.
Another advantage is that additional machining is not required to define the articulating bearing surface after the reforming of the articulating bearing surface under heat and pressure.